An electromechanical system in one example measures a parameter. For example, the electromechanical system comprises a micro-electromechanical system (“MEMS”) gyroscope that measures a rotation. The gyroscope in one example comprises a pendulous sensor component, a dither drive component, and a pickoff sensor. The dither drive component operates along a dither drive axis to set the pendulous sensor component into oscillation. The pendulous sensor component reacts to the rotation. The pickoff sensor obtains a value of the rotation from a motion of the pendulous sensor component.
One source of error in the rotation measurement is a bias sensitivity to changes in pressure. If the pressure is changing over time, then a model for bias compensation will be incorrect. In general, the Q of the gyroscope is inversely proportional to pressure for pressures below 1 mm of Hg (1 Torr). A bias may be introduced to the gyroscope by a misalignment of the dither drive that actuates the pendulous sensor component. The bias in one example increases a sensitivity to pressure of the gyroscope. As one shortcoming, the accuracy of the rotation measurement of the gyroscope decreases as pressure sensitivity increases.
Thus, a need exists for a reduction in a sensitivity to pressure of electromechanical systems.